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/*
* Copyright (C) 2011, 2014 Apple Inc. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "MemoryPressureHandler.h"
#include "CSSValuePool.h"
#include "Chrome.h"
#include "ChromeClient.h"
#include "DOMWindow.h"
#include "Document.h"
#include "FontCache.h"
#include "FontCascade.h"
#include "GCController.h"
#include "HTMLMediaElement.h"
#include "JSDOMWindow.h"
#include "MemoryCache.h"
#include "Page.h"
#include "PageCache.h"
#include "ScrollingThread.h"
#include "StyledElement.h"
#include "WorkerThread.h"
#include <JavaScriptCore/IncrementalSweeper.h>
#include <wtf/CurrentTime.h>
#include <wtf/FastMalloc.h>
#include <wtf/StdLibExtras.h>
namespace WebCore {
WEBCORE_EXPORT bool MemoryPressureHandler::ReliefLogger::s_loggingEnabled = false;
MemoryPressureHandler& MemoryPressureHandler::singleton()
{
static NeverDestroyed<MemoryPressureHandler> memoryPressureHandler;
return memoryPressureHandler;
}
MemoryPressureHandler::MemoryPressureHandler()
: m_installed(false)
, m_lastRespondTime(0)
, m_lowMemoryHandler([this] (Critical critical, Synchronous synchronous) { releaseMemory(critical, synchronous); })
, m_underMemoryPressure(false)
#if PLATFORM(IOS)
// FIXME: Can we share more of this with OpenSource?
, m_memoryPressureReason(MemoryPressureReasonNone)
, m_clearPressureOnMemoryRelease(true)
, m_releaseMemoryBlock(0)
, m_observer(0)
#elif OS(LINUX)
, m_eventFD(0)
, m_pressureLevelFD(0)
, m_threadID(0)
, m_holdOffTimer(*this, &MemoryPressureHandler::holdOffTimerFired)
#endif
{
}
void MemoryPressureHandler::releaseNoncriticalMemory()
{
{
ReliefLogger log("Purge inactive FontData");
FontCache::singleton().purgeInactiveFontData();
}
{
ReliefLogger log("Clear WidthCaches");
clearWidthCaches();
}
{
ReliefLogger log("Discard Selector Query Cache");
for (auto* document : Document::allDocuments())
document->clearSelectorQueryCache();
}
{
ReliefLogger log("Prune MemoryCache dead resources");
MemoryCache::singleton().pruneDeadResourcesToSize(0);
}
{
ReliefLogger log("Prune presentation attribute cache");
StyledElement::clearPresentationAttributeCache();
}
}
void MemoryPressureHandler::releaseCriticalMemory(Synchronous synchronous)
{
{
ReliefLogger log("Empty the PageCache");
// Right now, the only reason we call release critical memory while not under memory pressure is if the process is about to be suspended.
PruningReason pruningReason = isUnderMemoryPressure() ? PruningReason::MemoryPressure : PruningReason::ProcessSuspended;
PageCache::singleton().pruneToSizeNow(0, pruningReason);
}
{
ReliefLogger log("Prune MemoryCache live resources");
MemoryCache::singleton().pruneLiveResourcesToSize(0, /*shouldDestroyDecodedDataForAllLiveResources*/ true);
}
{
ReliefLogger log("Drain CSSValuePool");
CSSValuePool::singleton().drain();
}
{
ReliefLogger log("Discard StyleResolvers");
Vector<RefPtr<Document>> documents;
copyToVector(Document::allDocuments(), documents);
for (auto& document : documents)
document->clearStyleResolver();
}
{
ReliefLogger log("Discard all JIT-compiled code");
GCController::singleton().deleteAllCode();
}
#if ENABLE(VIDEO)
{
ReliefLogger log("Dropping buffered data from paused media elements");
for (auto* mediaElement: HTMLMediaElement::allMediaElements()) {
if (mediaElement->paused())
mediaElement->purgeBufferedDataIfPossible();
}
}
#endif
if (synchronous == Synchronous::Yes) {
ReliefLogger log("Collecting JavaScript garbage");
GCController::singleton().garbageCollectNow();
} else
GCController::singleton().garbageCollectNowIfNotDoneRecently();
// We reduce tiling coverage while under memory pressure, so make sure to drop excess tiles ASAP.
Page::forEachPage([](Page& page) {
page.chrome().client().scheduleCompositingLayerFlush();
});
}
void MemoryPressureHandler::releaseMemory(Critical critical, Synchronous synchronous)
{
if (critical == Critical::Yes)
releaseCriticalMemory(synchronous);
releaseNoncriticalMemory();
platformReleaseMemory(critical);
{
ReliefLogger log("Release free FastMalloc memory");
// FastMalloc has lock-free thread specific caches that can only be cleared from the thread itself.
WorkerThread::releaseFastMallocFreeMemoryInAllThreads();
#if ENABLE(ASYNC_SCROLLING) && !PLATFORM(IOS)
ScrollingThread::dispatch(WTF::releaseFastMallocFreeMemory);
#endif
WTF::releaseFastMallocFreeMemory();
}
}
#if !PLATFORM(COCOA) && !OS(LINUX) && !PLATFORM(WIN)
void MemoryPressureHandler::install() { }
void MemoryPressureHandler::uninstall() { }
void MemoryPressureHandler::holdOff(unsigned) { }
void MemoryPressureHandler::respondToMemoryPressure(Critical, Synchronous) { }
void MemoryPressureHandler::platformReleaseMemory(Critical) { }
void MemoryPressureHandler::ReliefLogger::platformLog() { }
size_t MemoryPressureHandler::ReliefLogger::platformMemoryUsage() { return 0; }
#endif
} // namespace WebCore
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